Saturday 10 November 2012 12.12 EST
First published on Saturday 10 November 2012 12.12 EST

The story of biographer Paula Broadwell, whose affair with General David Petraeus resulted in his resignation from the CIA this week, has got everyone talking about the official code of conduct at Langley.

But what about the other side? Is there a code of conduct for biographers? If there is, it's a lot less clear.

Academics refer to biographies as "The Study of Another Self," which might explain how the process of writing one resembles an affair.

First, there is the intense and at times all-consuming focus on one other person. Then there is stuff you hope the larger world won't find out about. There's the courtship, when you write emails and place phone calls you hope the public will never see or hear as you woo your subject.

There's flattery, seduction, and attempts to establish intimacy that you realize are a means to an end, but that if seen by others would be embarrassing and humiliating – to you.

An authorized biography, where the subject cooperates with the writer, allows an intimate relationship between the two to develop.

An unauthorized biography, like his, immediately takes on a clandestine element. There are secret meetings – more often with enemies than with friends – interviews with the disenchanted, and a sifting through gossip. An unauthorized biographer is more like a stalker than a lover.

Many years ago, I wrote a biography of Winnie Mandela. It was completely unauthorized, to the point where I was given to know by Mrs Mandela's team that proceeding with it was a dangerous enterprise. But she never interfered with the process, never told anyone not to talk to me, and when asked, talked about it with a kind of disparaging acceptance that I found a relief.

Still, as I pored through her documents, dug through boxes of belongings and read letters she had long abandoned, I felt a sense of sympathy for her. I was violating her privacy. I also learned that the more your subject is humanized by whatever contact you establish, the more compassion you feel. It was the spelling mistakes I saw in essays Mrs Mandela wrote in correspondence courses she took while in exile that made me feel sorry for her.

Harry Hurt III took on another big-name target when he wrote a biography of Donald Trump, "Lost Tycoon: Many Lives of Donald J Trump" at a low point in Trump's professional career.

The book was unauthorized, but Trump "didn't stand in my way, he's the greatest self-promoter of all time", says Hurt.

Hurt says that over the course of his work, he did "gain a little more sympathy for the devil," but is quick to point out the difference between sympathy and empathy.

"Sympathy is when you like the person," he says. "Empathy is when you say he or she is like me. I recognized in Trump certain traits that I recognize in myself – and in all of us."

Hurt believes that the ideal relationship in biography is when you could have access to your subject but not be beholden.

Unauthorized celebrity biographer Kitty Kelley put that well when she said there's a point "where the biographer either sells his soul for the cozy dinners or bails for the truth."

Authorized biographies often involves an element of betrayal – having wooed and flattered and listened to your subject with sympathetic attention, if you're good at your job, you'll regain your independence and end up writing at least something your subject won't like.

Vanity Fair writer Bob Colacello, who is writing a two-volume biography of Ronald and Nancy Reagan – with Nancy Reagan as his primary source – says he always gets as close as possible to his subject during the interview process. Afterwards, "I always break off contact with them," he says. "I have to transfer them into a subject – into an object – I don't want any more input from them. Even fact checking can be a treacherous process – they start rewriting, even quotes."

When Colacello sent Mrs Reagan bound galleys of his first volume: "Ronald and Nancy Reagan, The Path to the White House, 1911-1981" he didn't hear from her for 6 weeks. She was offended by some of his portrayal of her. But eventually she came round and started to follow his book tour on TV, calling him after appearances and instructing him to use the word "love" repeatedly in his description of her motivation. She continues to cooperate with the second volume.

Recently, the worst breach between subject and biographer was in Jeff Himmelman's "Yours in Truth: A Personal Portrait of Ben Bradlee," a book that was savaged by Bradlee's friends and wife when it came out earlier this year. Why? Bradlee and his family had given Himmelman extraordinary access – to their archives, friends and co-workers. Bradlee had even instructed Himmelman to write whatever he wanted.

"The relationship I had while I was working on the book – I couldn't have asked for anything more," said Himmelman in an interview this morning.

"The time I spent with Bradlee and with Sally and with the whole family was a really wonderful part of my life."

But, "You're choosing the story to tell," he added. And so he did – to howls of outrage from the Bradlee faction, who hated his take on Bradlee's legacy.

They never attacked a fact in the book, but they launched a personal attack on Himmelman that was vitriolic in the extreme.

"It leaves a taste in my mouth that I just can't get out," he says, adding that his next biography will most likely be of a dead person.

Things are easier when the subject is dead. In that case, Walter Isaacson had it easiest of all. He wrote an authorized biography of Steve Jobs with extraordinary access while Jobs was alive. But Jobs never read the book, which was published after he died.

In an interview after the book was published, Isaacson explained the tension involved in writing. "When writing about a living subject who is willing to give unlimited interviews, you end up knowing countless times more than you do about a historical figure. And what you know can just as well be a source of sympathy as well as a provocation to unmasking. Perhaps that [sympathy] was a flaw caused by getting to know him," he said.

Paula Broadwell didn't betray her subject while writing the book or promoting it, possibly because of the kind of relationship the two had developed. Reviews of her book call it "hagiographic" and full of "hero worship." The betrayal, however it came, came later.

In the end, biographers are much like spies. They seduce their subjects into telling their secrets, which they then use for their own purposes. When they are done, they cast their subject aside, ready to move onto the next. In that sense, the relationship between the Director of the CIA and his biographer was beautifully symmetrical.